基于双向变流装置的城市轨道牵引供电系统潮流计算

基于双向变流装置输出外特性,分析电压调整率与下垂率的关系;以电压源换流器模型为基础,建立考虑下垂输出外特性的双向变流装置计算模型;采用交直流一体迭代潮流算法,进行含双向变流装置的城市轨道牵引供电系统潮流计算。以某地铁工程为例,列车采用6B编组,最高时速为80km·h^-1,研究双向变流装置下垂率和空载电压对峰值功率、牵引网网压和钢轨电位的影响。结果表明:随着输出外特性中下垂率的增长,双向变流装置峰值功率需求降低,但牵引网网压波动加剧,钢轨电位提高;当空载电压在1 500~1 650V范围内、下垂率为0.055~0.06时,全线牵引降压混合所整流工况的峰值功率最大在7 146~7 320kW之间。在实际工程中,应选取适当的下垂率和电压调整率,允许部分功率跨区间传输,以降低双向变流装置的安装容量,同时兼顾牵引网网压和钢轨电位的控制需求。

Power Flow of Traction Power Supply System for Urban Rail Transit Based on Bidirectional Converter Device

Based on the output external characteristics of bidirectional converter device,the relationship between the voltage regulation rate and the droop rate was analyzed.The calculation model of bidirectional converter device considering the external characteristics of droop output was established based on the voltage source converter(VSC)model.The AC/DC integrated iterative power flow algorithm was used to calculate the power flow of urban rail traction power supply system with bidirectional converter device.Taking a subway project as an example,the train formation was 6 Bwith the maximum speed of 80 km·h^-1.The influence of the droop rate and no-load voltage of the bidirectional converter device on the peak power,traction network voltage and rail potential was studied.Results show that with the increase of the droop rate in the output external characteristics,the peak power demand of the bidirectional converter reduces,but the fluctuation of the traction network voltage and the rail potential increase.When the no-load voltage is in the range of 1 500~1 650 Vand the droop rate is between 0.055 and 0.06,the maximum peak power of the traction step-down hybrid substations of the whole line under rectification condition is between 7 146 and 7 320 kW.In practical engineering,appropriate droop rate and voltage regulation rate should be selected to allow part of power to be transmitted across sections so as to reduce the installation capacity of the bidirectional converter device,meanwhile,taking into account the control requirements of the traction network voltage and rail potential.